Lefting-jack



R. B. IESTER.

Llfms JACK. APPLICATION FILED MAY 22. ISIH.

y 1 INVENTOR i; @met (mm ms Iva/ems Pzrsns co.. Fumo-urna., wasumcmu. nA c.

55 frame is the shaft 11. The bearings 9 and RONALD B. JESTER, or NEW CUMBEBLAN'D, wnsr vrneiNrn. i

LIFTING-J ACK.

Specification of LettersPatent. v] )g,|,1ge11ged Mia'y 1919.

Application led Mayr 22, 1918. Serial No. 235,917.

To all whom t may concern Be it known that I, RONALD B. Jns'rER, a citizen of the United States, and residentof New Cumberland, in the county of Hancock and State of West Virginia, have invented a new and useful Improvement in Lifting- Jacks, (Case 2;) and I do hereby declare the following to be a' full, clear, and exact description thereof.

My invention relates-to lifting-jacks, and more especially to the type of jack illustrated and described in an application filed byme January 11, 1 918, Serial No. 211,331, in which the lifting-bar has oppositely-disposed teeth and a'lifting-pawl working between said teeth, said Alifting-'pawl ibeing raised and lowered, and when in engagement with the teeth on one side, the lifting of the bar is accomplished, and when the liftingbar has reached the limit of its upward movement, the lifting-pawl is shifted automatically to theopposite set of teeth and the lifting-barlowered step by step.

The object of the present invention is to provide a new form of mechanism for shifting the lifting and lowering pawl, which has some advantage over the construction (of said application, and the invention comprises the novel features hereinafter set forth and claimed. l i

In the accompanying drawing, Figure 1 is a side view of my jack; Fig. 2is a vertical section; Fig. Sis asection on the line 3` -3, Fig. 2; Fig. L shows the position of the lifting and lowering-pawl with the lifting-bar at `the upper limit of.-V its stroke and in po'sitionforV shifting; Fig. 5 shows the lifting and lowering-pawl after it has been shifted to reversing positions; Fig. l6 fis 'a detail showing the position of they holding pawl in the lowering operation; Figi'Z-is a view of the holding pawl in position for shifting the lifting and lowering pawl back to raising position;`and Fig. 8 is a perspective view of the holding-pawl.

In the drawing, the numeral 2 designates a suitableframe or casing for containing the parts, supportedon a base, 3 Fitting within the casing 2 is the llifting-bar 4, which is yadapted to move up and down with said casing as al guide, and said bar has the recessed portion 5 with the oppositely-disposed teeth 6 and 7. In the rear of the bar are the teeth 8.

Journaled in bearings 9 and 10 in the 10 are arranged at an angle, as illustrated 1n. Fig. 3for convenience in operation, and the outer endof the shaft 11 has the wrenchseat .12 for the attachment of a wrench to impart a rotary movement to said shaft. The inner end of said shaft has ball-bearings to'relieve the thrust-friction. It will be apparent that by having the" shaft arranged at an angle the operator doesnot have to stoop so low, and there is less chance for interference with the ground in the'turning of said shaft. Y f

VThe shaft 11 is provided with the crank 13, and said crank engages the lower end-of the lifting and lowering-pawl 14,so that by the rotation of the shaft 11 an upward and downward movement islimparted to said lifting and lowering-pawl. The lower end of said pawl is .bent as at 15' to conform to the angular position of the shaft 11, while the upper portion of said-pawl is parallel to the walls of the frame 2. At the upper end of the pawl 14 is the lugor enlargement 16, which is triangular in form, and within said lug is the seat 17 to receive the pin 18, a spring 19 being interposed between.`

a plug and thehead 2O of said pin whereby said pin is adapted to yield under certain conditions. I l

A holding-pawl 21'is provided whichfis pivotally-mounted on the frame at 22, said pawl having the teeth 23, whichen age the teeth 8 on the rear ofthe liftingar, and said teeth are held normally in engagement with said teeth on the liftin -bar by the springv 25. The holdingaw V21 has the face 26,. which is engaged y the pin 18 in the raising of the lifting-bar, and alcamvface 27, which is engaged by the pin during the lowering operation vof the liftingbar, and a' shoulder 21a,-preferably a continuationof the cam-face 27,-adapted to be engagedby the pin 17 for tripping the pawl, all as fully hereinafter set forth.

The lower end of the lifting-bar l has the camelug 28, which acts to shift the pawl b-y its engagement-with the llug 16 on said pawl, as fully hereinafter set forth. l

A spring 29 is secured .to the inside of the framel 2 and saidspring bears 'against one side of the lifting and lowering-pawl 141, and said spring acts to shift said pawl when the lifting-bar has been lowered to bring rear face just above the toothed portion 8 is the recess 30 of less depth than the teeth 8, and with which the pawl teeth 23 engage when the lifting-bar has reached its lower limit of movement.

In the operation of my improved jack, with the pawl 1li in the position indicated in Fig. 2, a suitable crank is applied to the seat 12 of the shaft 11, and a. rotary movement imparted to said shaft. This will act to alternately raise and lower the pawl 14, and the lug 16 yat the upper end. of said pawl engaging the teeth 6 on the right-hand side of the lifting-bar will raise the liftingbar by step by step motion, the holdingpawl 21 moving in and out by the action of the spring 25 so as to hold t-he lifting-bar in its raised position while the pawl 14 is bveing lowered to engage another tooth. The lifting-bar is lifted in this manner until vthe cam-lug 28 at the lower end of said bar engages the triangular-shaped lug 16k of the pawl 14, whereupon said pawl is shifted to the left to engage the teeth 7. In this movement of the pawl 1st, the pin 18 moves diagonally from its position on the face 26 until it passes over the raised portion 32 and is forced by the spring 19 into position for engagement with the cam-face 27 of the holding-pawl 21.

By the continued rotation of the shaft 11 in the same direction, the lowering of the lifting-bar now takes place; the pin moving along the cam face 27 on the upstroke of the pawl directs the pawl to engage with Vthe teeth 7, as indicated in Fig. 5. Upward movement of the pawl carries the pin into engagement with the shoulder 2la of the holding-pawl 21, tripping said pawl, as clearly shown in Fig. 6. This tripping of the holding-pawl takes place substantially at completion of the upstroke, the pin 18 acting to hold said pawl out of engagement with the holding ratchetsl until the liftingbar has lowered suiiciently to allow for the engagement of the pawl with the neXt higher ratchet.

In this way by step by. step movement, the lifting-bar is lowered,'and finally with the pawl-teeth 23 engage the recess 3,0 in the lifting-bar, and as said recess is of less depth than the teeth 8, the pawl 21 is held from moving intol its normal position, as indicated in Fig. 7. When the pawl 14 is lowered with the holding-pawl 21 in this position, the pin 17 will then p ass below the cam-face 27, as indicated in Fig. 7, whereupon the spring 29 forces the pawl 14 over again into engagement with the teeth 6 in position for again raising the lifting-bar.

lVhat I claim is:

vl. In a lifting-jack, the combination with a. 'suitable fra-me, of a lifting-bar having oppositely-disposed teeth,

a holding-pawl, teeth on said lifting-barv engaged by said -ering-pawl. 4 I 5. In a lifting-jack, the combination with vholding-pawl, lifting and lowering-pawl arranged between said oppositely-disposed teeth, means carried by said frame for raising and lowering said last-named pawl, means carried by said lifting-bar adapted to move said last-named pawl from one set of teeth to the other, a yielding-pin carried by said last-named pawl, a cam-face on said holding-pawl adapted to be engaged by said pin, and means for tripping said holdingpawl Vby the movement of said pin.

2. In a lifting-jack, the combination with a suitable frame, of a lifting-bar having oppositely-.disposed teeth, a holding-pawl, t

a suitable frame, of a lifting-bar having oppositely-disposed teeth, a spring-actuated holding-pawl, teeth on said lifting-bar enfgaged by said holding-pawl, a lifting vand 3. In a lifting-jack, the combination with f,

lowering-pawl arranged between said oppositely-disposed teeth, means carried by said lifting-bar for shifting said last-named-pawl from one set of teeth to the other, means carried by said frame for raising-and lowering said last-named pawl, a yielding-,pin mounted in said last-named'pawl movable in engagement with a plain face of said holdingpawl during the lifting of the lifting-bar, a cam-.face on said holding-pawl engaged by said pin during the 'lowering of said lift- 'ing-bar and means for tripping saidY holding-pawl by the movement of said pin.

4f In a lifting-Jack, .the Combination vwith Va suitable frame,l Ogf a lifting-bar having opspring-.actuated -V positely-disposed teeth, a

holding-pawl, teeth on'said lifting-bar engaged by said holding-pawl, a notch formed in said lifting-bar above said last-.named teeth ef less depth than said last-named teeth, a lifting and lowering-pawl arranged between saidv eppositely-disposed teeth, means carried by said frame for raising and lowering said last-named pawl,l means carried by the lifting-,bar for shifting. said last-named pawl from One set of teeth yielding-pin carried by said last-named pawl, a bcam-face on said holding-pawl Aadapted' to be engaged by said pin, and; a

spring bearing against said lifting and lowto the other, -a .j .v

a suitable frame, of a lifting-bar having oppositely-disposed teeth, a spring-actuated holding-pawl, means for holding said holding-pawl out of engagement with said teeth when the lifting-bar has been completely lowered, a lifting and lowering-pawl arranged between said oppositely-disposed teeth, means carried by said frame for raising and lowering said last-named pawl, and means for shifting said last-named pawl from one set of teeth to the other.

6. In a lifting-jack, the combination with a suitable frame, of a lifting-bar having oppositely-disposed teeth, a spring-actuated holding-pawl, teeth on said lifting-bar engaged by said holding-pawl, a lifting and lowering-pawl arranged between said oppositely-disposed teeth, means carried by said lifting-bar for shifting said last-named pawl from one set of teeth to the other, means carried by said frame for raising and lowering said last-named pawl, a yielding pin mount- Copiel of this patent may be obtained for dve cents each,

ed in said last-named pawl, a cam-face on said holding-pawl engaged by said pin during the lowering of said lifting-bar, and a projection on said holding-pawl engaged b said pin whereby Said holding-pawl is move out of engagement with the teeth on said lifting-bar.

7. In a lifting jack, the combination with a suitable frame, of a lifting bar having teeth, a holding pawl, a lifting and lowering pawl, a rotary shaft in said frame inclined downwardly from its operating end, and connections between said shaft and said lifting and lowering pawl for operating the same. Y

In testimony whereof, I, the said RONALD B. J ESTER, have hereunto set my hand.

RONALD B. JESTER.

Witnesses: C. M. SCOPI',

A. K. CARROLL.

by addressing the Commissioner ot latenti,

Washington, D. G." 

